Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quem era o parceiro de Betty quando a superfície está dura?
 ###Tabelas: CREATE TABLE m (m_id AUTO_INCREMENT PRIMARY KEY, Artist VARCHAR, Country VARCHAR, Number-one single(s) VARCHAR, Year INT, Weeks at #1 INT, Straight to #1 ? VARCHAR) CREATE TABLE winners_of_the_circuit_des_ardennes (winners_of_the_circuit_des_ardennes_id AUTO_INCREMENT PRIMARY KEY, Year INT, Formula VARCHAR, Driver VARCHAR, Constructor VARCHAR, Location VARCHAR, Report VARCHAR) CREATE TABLE results_in_presidential_elections (results_in_presidential_elections_id AUTO_INCREMENT PRIMARY KEY, Year INT, Candidate VARCHAR, State(s) on the Ballot VARCHAR, Popular Votes INT, Percentage VARCHAR) CREATE TABLE list_of_rural_communities_in_new_brunswick (list_of_rural_communities_in_new_brunswick_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Population (2011) INT, Population (2006) INT, Change (%) VARCHAR, Area (km²) VARCHAR, Population density VARCHAR) CREATE TABLE women's_doubles:_14_6_titles_8_runner-ups (women's_doubles:_14_6_titles_8_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents in the final VARCHAR, Score in the final VARCHAR)  
SELECT Partner FROM women's_doubles:_14_6_titles_8_runner-ups WHERE Surface = Hard